1 /*
2 * Copyright 2005-2022 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <limits.h>
11 #include <string.h>
12 #include <stdio.h>
13 #include "../ssl_local.h"
14 #include "statem_local.h"
15 #include "internal/cryptlib.h"
16 #include <openssl/buffer.h>
17 #include <openssl/objects.h>
18 #include <openssl/evp.h>
19 #include <openssl/x509.h>
20
21 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
22
23 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
24 if ((end) - (start) <= 8) { \
25 long ii; \
26 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
27 } else { \
28 long ii; \
29 bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
30 for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
31 bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
32 } }
33
34 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
35 long ii; \
36 is_complete = 1; \
37 if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
38 if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
39 if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
40
41 static unsigned char bitmask_start_values[] =
42 { 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 };
43 static unsigned char bitmask_end_values[] =
44 { 0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f };
45
46 static void dtls1_fix_message_header(SSL *s, size_t frag_off,
47 size_t frag_len);
48 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p);
49 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
50 size_t len,
51 unsigned short seq_num,
52 size_t frag_off,
53 size_t frag_len);
54 static int dtls_get_reassembled_message(SSL *s, int *errtype, size_t *len);
55
dtls1_hm_fragment_new(size_t frag_len,int reassembly)56 static hm_fragment *dtls1_hm_fragment_new(size_t frag_len, int reassembly)
57 {
58 hm_fragment *frag = NULL;
59 unsigned char *buf = NULL;
60 unsigned char *bitmask = NULL;
61
62 if ((frag = OPENSSL_zalloc(sizeof(*frag))) == NULL) {
63 ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
64 return NULL;
65 }
66
67 if (frag_len) {
68 if ((buf = OPENSSL_malloc(frag_len)) == NULL) {
69 ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
70 OPENSSL_free(frag);
71 return NULL;
72 }
73 }
74
75 /* zero length fragment gets zero frag->fragment */
76 frag->fragment = buf;
77
78 /* Initialize reassembly bitmask if necessary */
79 if (reassembly) {
80 bitmask = OPENSSL_zalloc(RSMBLY_BITMASK_SIZE(frag_len));
81 if (bitmask == NULL) {
82 ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
83 OPENSSL_free(buf);
84 OPENSSL_free(frag);
85 return NULL;
86 }
87 }
88
89 frag->reassembly = bitmask;
90
91 return frag;
92 }
93
dtls1_hm_fragment_free(hm_fragment * frag)94 void dtls1_hm_fragment_free(hm_fragment *frag)
95 {
96 if (!frag)
97 return;
98
99 OPENSSL_free(frag->fragment);
100 OPENSSL_free(frag->reassembly);
101 OPENSSL_free(frag);
102 }
103
104 /*
105 * send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or
106 * SSL3_RT_CHANGE_CIPHER_SPEC)
107 */
dtls1_do_write(SSL * s,int type)108 int dtls1_do_write(SSL *s, int type)
109 {
110 int ret;
111 size_t written;
112 size_t curr_mtu;
113 int retry = 1;
114 size_t len, frag_off, mac_size, blocksize, used_len;
115
116 if (!dtls1_query_mtu(s))
117 return -1;
118
119 if (s->d1->mtu < dtls1_min_mtu(s))
120 /* should have something reasonable now */
121 return -1;
122
123 if (s->init_off == 0 && type == SSL3_RT_HANDSHAKE) {
124 if (!ossl_assert(s->init_num ==
125 s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH))
126 return -1;
127 }
128
129 if (s->write_hash) {
130 if (s->enc_write_ctx
131 && (EVP_CIPHER_get_flags(EVP_CIPHER_CTX_get0_cipher(s->enc_write_ctx)) &
132 EVP_CIPH_FLAG_AEAD_CIPHER) != 0)
133 mac_size = 0;
134 else
135 mac_size = EVP_MD_CTX_get_size(s->write_hash);
136 } else
137 mac_size = 0;
138
139 if (s->enc_write_ctx &&
140 (EVP_CIPHER_CTX_get_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
141 blocksize = 2 * EVP_CIPHER_CTX_get_block_size(s->enc_write_ctx);
142 else
143 blocksize = 0;
144
145 frag_off = 0;
146 s->rwstate = SSL_NOTHING;
147
148 /* s->init_num shouldn't ever be < 0...but just in case */
149 while (s->init_num > 0) {
150 if (type == SSL3_RT_HANDSHAKE && s->init_off != 0) {
151 /* We must be writing a fragment other than the first one */
152
153 if (frag_off > 0) {
154 /* This is the first attempt at writing out this fragment */
155
156 if (s->init_off <= DTLS1_HM_HEADER_LENGTH) {
157 /*
158 * Each fragment that was already sent must at least have
159 * contained the message header plus one other byte.
160 * Therefore |init_off| must have progressed by at least
161 * |DTLS1_HM_HEADER_LENGTH + 1| bytes. If not something went
162 * wrong.
163 */
164 return -1;
165 }
166
167 /*
168 * Adjust |init_off| and |init_num| to allow room for a new
169 * message header for this fragment.
170 */
171 s->init_off -= DTLS1_HM_HEADER_LENGTH;
172 s->init_num += DTLS1_HM_HEADER_LENGTH;
173 } else {
174 /*
175 * We must have been called again after a retry so use the
176 * fragment offset from our last attempt. We do not need
177 * to adjust |init_off| and |init_num| as above, because
178 * that should already have been done before the retry.
179 */
180 frag_off = s->d1->w_msg_hdr.frag_off;
181 }
182 }
183
184 used_len = BIO_wpending(s->wbio) + DTLS1_RT_HEADER_LENGTH
185 + mac_size + blocksize;
186 if (s->d1->mtu > used_len)
187 curr_mtu = s->d1->mtu - used_len;
188 else
189 curr_mtu = 0;
190
191 if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
192 /*
193 * grr.. we could get an error if MTU picked was wrong
194 */
195 ret = BIO_flush(s->wbio);
196 if (ret <= 0) {
197 s->rwstate = SSL_WRITING;
198 return ret;
199 }
200 used_len = DTLS1_RT_HEADER_LENGTH + mac_size + blocksize;
201 if (s->d1->mtu > used_len + DTLS1_HM_HEADER_LENGTH) {
202 curr_mtu = s->d1->mtu - used_len;
203 } else {
204 /* Shouldn't happen */
205 return -1;
206 }
207 }
208
209 /*
210 * We just checked that s->init_num > 0 so this cast should be safe
211 */
212 if (((unsigned int)s->init_num) > curr_mtu)
213 len = curr_mtu;
214 else
215 len = s->init_num;
216
217 if (len > ssl_get_max_send_fragment(s))
218 len = ssl_get_max_send_fragment(s);
219
220 /*
221 * XDTLS: this function is too long. split out the CCS part
222 */
223 if (type == SSL3_RT_HANDSHAKE) {
224 if (len < DTLS1_HM_HEADER_LENGTH) {
225 /*
226 * len is so small that we really can't do anything sensible
227 * so fail
228 */
229 return -1;
230 }
231 dtls1_fix_message_header(s, frag_off, len - DTLS1_HM_HEADER_LENGTH);
232
233 dtls1_write_message_header(s,
234 (unsigned char *)&s->init_buf->
235 data[s->init_off]);
236 }
237
238 ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off], len,
239 &written);
240 if (ret <= 0) {
241 /*
242 * might need to update MTU here, but we don't know which
243 * previous packet caused the failure -- so can't really
244 * retransmit anything. continue as if everything is fine and
245 * wait for an alert to handle the retransmit
246 */
247 if (retry && BIO_ctrl(SSL_get_wbio(s),
248 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) {
249 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
250 if (!dtls1_query_mtu(s))
251 return -1;
252 /* Have one more go */
253 retry = 0;
254 } else
255 return -1;
256 } else {
257 return -1;
258 }
259 } else {
260
261 /*
262 * bad if this assert fails, only part of the handshake message
263 * got sent. but why would this happen?
264 */
265 if (!ossl_assert(len == written))
266 return -1;
267
268 if (type == SSL3_RT_HANDSHAKE && !s->d1->retransmitting) {
269 /*
270 * should not be done for 'Hello Request's, but in that case
271 * we'll ignore the result anyway
272 */
273 unsigned char *p =
274 (unsigned char *)&s->init_buf->data[s->init_off];
275 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
276 size_t xlen;
277
278 if (frag_off == 0 && s->version != DTLS1_BAD_VER) {
279 /*
280 * reconstruct message header is if it is being sent in
281 * single fragment
282 */
283 *p++ = msg_hdr->type;
284 l2n3(msg_hdr->msg_len, p);
285 s2n(msg_hdr->seq, p);
286 l2n3(0, p);
287 l2n3(msg_hdr->msg_len, p);
288 p -= DTLS1_HM_HEADER_LENGTH;
289 xlen = written;
290 } else {
291 p += DTLS1_HM_HEADER_LENGTH;
292 xlen = written - DTLS1_HM_HEADER_LENGTH;
293 }
294
295 if (!ssl3_finish_mac(s, p, xlen))
296 return -1;
297 }
298
299 if (written == s->init_num) {
300 if (s->msg_callback)
301 s->msg_callback(1, s->version, type, s->init_buf->data,
302 (size_t)(s->init_off + s->init_num), s,
303 s->msg_callback_arg);
304
305 s->init_off = 0; /* done writing this message */
306 s->init_num = 0;
307
308 return 1;
309 }
310 s->init_off += written;
311 s->init_num -= written;
312 written -= DTLS1_HM_HEADER_LENGTH;
313 frag_off += written;
314
315 /*
316 * We save the fragment offset for the next fragment so we have it
317 * available in case of an IO retry. We don't know the length of the
318 * next fragment yet so just set that to 0 for now. It will be
319 * updated again later.
320 */
321 dtls1_fix_message_header(s, frag_off, 0);
322 }
323 }
324 return 0;
325 }
326
dtls_get_message(SSL * s,int * mt)327 int dtls_get_message(SSL *s, int *mt)
328 {
329 struct hm_header_st *msg_hdr;
330 unsigned char *p;
331 size_t msg_len;
332 size_t tmplen;
333 int errtype;
334
335 msg_hdr = &s->d1->r_msg_hdr;
336 memset(msg_hdr, 0, sizeof(*msg_hdr));
337
338 again:
339 if (!dtls_get_reassembled_message(s, &errtype, &tmplen)) {
340 if (errtype == DTLS1_HM_BAD_FRAGMENT
341 || errtype == DTLS1_HM_FRAGMENT_RETRY) {
342 /* bad fragment received */
343 goto again;
344 }
345 return 0;
346 }
347
348 *mt = s->s3.tmp.message_type;
349
350 p = (unsigned char *)s->init_buf->data;
351
352 if (*mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
353 if (s->msg_callback) {
354 s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
355 p, 1, s, s->msg_callback_arg);
356 }
357 /*
358 * This isn't a real handshake message so skip the processing below.
359 */
360 return 1;
361 }
362
363 msg_len = msg_hdr->msg_len;
364
365 /* reconstruct message header */
366 *(p++) = msg_hdr->type;
367 l2n3(msg_len, p);
368 s2n(msg_hdr->seq, p);
369 l2n3(0, p);
370 l2n3(msg_len, p);
371
372 memset(msg_hdr, 0, sizeof(*msg_hdr));
373
374 s->d1->handshake_read_seq++;
375
376 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
377
378 return 1;
379 }
380
381 /*
382 * Actually we already have the message body - but this is an opportunity for
383 * DTLS to do any further processing it wants at the same point that TLS would
384 * be asked for the message body.
385 */
dtls_get_message_body(SSL * s,size_t * len)386 int dtls_get_message_body(SSL *s, size_t *len)
387 {
388 unsigned char *msg = (unsigned char *)s->init_buf->data;
389 size_t msg_len = s->init_num + DTLS1_HM_HEADER_LENGTH;
390
391 if (s->s3.tmp.message_type == SSL3_MT_CHANGE_CIPHER_SPEC) {
392 /* Nothing to be done */
393 goto end;
394 }
395 /*
396 * If receiving Finished, record MAC of prior handshake messages for
397 * Finished verification.
398 */
399 if (*(s->init_buf->data) == SSL3_MT_FINISHED && !ssl3_take_mac(s)) {
400 /* SSLfatal() already called */
401 return 0;
402 }
403
404 if (s->version == DTLS1_BAD_VER) {
405 msg += DTLS1_HM_HEADER_LENGTH;
406 msg_len -= DTLS1_HM_HEADER_LENGTH;
407 }
408
409 if (!ssl3_finish_mac(s, msg, msg_len))
410 return 0;
411
412 if (s->msg_callback)
413 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
414 s->init_buf->data, s->init_num + DTLS1_HM_HEADER_LENGTH,
415 s, s->msg_callback_arg);
416
417 end:
418 *len = s->init_num;
419 return 1;
420 }
421
422 /*
423 * dtls1_max_handshake_message_len returns the maximum number of bytes
424 * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but
425 * may be greater if the maximum certificate list size requires it.
426 */
dtls1_max_handshake_message_len(const SSL * s)427 static size_t dtls1_max_handshake_message_len(const SSL *s)
428 {
429 size_t max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
430 if (max_len < s->max_cert_list)
431 return s->max_cert_list;
432 return max_len;
433 }
434
dtls1_preprocess_fragment(SSL * s,struct hm_header_st * msg_hdr)435 static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr)
436 {
437 size_t frag_off, frag_len, msg_len;
438
439 msg_len = msg_hdr->msg_len;
440 frag_off = msg_hdr->frag_off;
441 frag_len = msg_hdr->frag_len;
442
443 /* sanity checking */
444 if ((frag_off + frag_len) > msg_len
445 || msg_len > dtls1_max_handshake_message_len(s)) {
446 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_EXCESSIVE_MESSAGE_SIZE);
447 return 0;
448 }
449
450 if (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */
451 /*
452 * msg_len is limited to 2^24, but is effectively checked against
453 * dtls_max_handshake_message_len(s) above
454 */
455 if (!BUF_MEM_grow_clean(s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) {
456 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_BUF_LIB);
457 return 0;
458 }
459
460 s->s3.tmp.message_size = msg_len;
461 s->d1->r_msg_hdr.msg_len = msg_len;
462 s->s3.tmp.message_type = msg_hdr->type;
463 s->d1->r_msg_hdr.type = msg_hdr->type;
464 s->d1->r_msg_hdr.seq = msg_hdr->seq;
465 } else if (msg_len != s->d1->r_msg_hdr.msg_len) {
466 /*
467 * They must be playing with us! BTW, failure to enforce upper limit
468 * would open possibility for buffer overrun.
469 */
470 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_EXCESSIVE_MESSAGE_SIZE);
471 return 0;
472 }
473
474 return 1;
475 }
476
477 /*
478 * Returns 1 if there is a buffered fragment available, 0 if not, or -1 on a
479 * fatal error.
480 */
dtls1_retrieve_buffered_fragment(SSL * s,size_t * len)481 static int dtls1_retrieve_buffered_fragment(SSL *s, size_t *len)
482 {
483 /*-
484 * (0) check whether the desired fragment is available
485 * if so:
486 * (1) copy over the fragment to s->init_buf->data[]
487 * (2) update s->init_num
488 */
489 pitem *item;
490 piterator iter;
491 hm_fragment *frag;
492 int ret;
493 int chretran = 0;
494
495 iter = pqueue_iterator(s->d1->buffered_messages);
496 do {
497 item = pqueue_next(&iter);
498 if (item == NULL)
499 return 0;
500
501 frag = (hm_fragment *)item->data;
502
503 if (frag->msg_header.seq < s->d1->handshake_read_seq) {
504 pitem *next;
505 hm_fragment *nextfrag;
506
507 if (!s->server
508 || frag->msg_header.seq != 0
509 || s->d1->handshake_read_seq != 1
510 || s->statem.hand_state != DTLS_ST_SW_HELLO_VERIFY_REQUEST) {
511 /*
512 * This is a stale message that has been buffered so clear it.
513 * It is safe to pop this message from the queue even though
514 * we have an active iterator
515 */
516 pqueue_pop(s->d1->buffered_messages);
517 dtls1_hm_fragment_free(frag);
518 pitem_free(item);
519 item = NULL;
520 frag = NULL;
521 } else {
522 /*
523 * We have fragments for a ClientHello without a cookie,
524 * even though we have sent a HelloVerifyRequest. It is possible
525 * that the HelloVerifyRequest got lost and this is a
526 * retransmission of the original ClientHello
527 */
528 next = pqueue_next(&iter);
529 if (next != NULL) {
530 nextfrag = (hm_fragment *)next->data;
531 if (nextfrag->msg_header.seq == s->d1->handshake_read_seq) {
532 /*
533 * We have fragments for both a ClientHello without
534 * cookie and one with. Ditch the one without.
535 */
536 pqueue_pop(s->d1->buffered_messages);
537 dtls1_hm_fragment_free(frag);
538 pitem_free(item);
539 item = next;
540 frag = nextfrag;
541 } else {
542 chretran = 1;
543 }
544 } else {
545 chretran = 1;
546 }
547 }
548 }
549 } while (item == NULL);
550
551 /* Don't return if reassembly still in progress */
552 if (frag->reassembly != NULL)
553 return 0;
554
555 if (s->d1->handshake_read_seq == frag->msg_header.seq || chretran) {
556 size_t frag_len = frag->msg_header.frag_len;
557 pqueue_pop(s->d1->buffered_messages);
558
559 /* Calls SSLfatal() as required */
560 ret = dtls1_preprocess_fragment(s, &frag->msg_header);
561
562 if (ret && frag->msg_header.frag_len > 0) {
563 unsigned char *p =
564 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
565 memcpy(&p[frag->msg_header.frag_off], frag->fragment,
566 frag->msg_header.frag_len);
567 }
568
569 dtls1_hm_fragment_free(frag);
570 pitem_free(item);
571
572 if (ret) {
573 if (chretran) {
574 /*
575 * We got a new ClientHello with a message sequence of 0.
576 * Reset the read/write sequences back to the beginning.
577 * We process it like this is the first time we've seen a
578 * ClientHello from the client.
579 */
580 s->d1->handshake_read_seq = 0;
581 s->d1->next_handshake_write_seq = 0;
582 }
583 *len = frag_len;
584 return 1;
585 }
586
587 /* Fatal error */
588 s->init_num = 0;
589 return -1;
590 } else {
591 return 0;
592 }
593 }
594
595 static int
dtls1_reassemble_fragment(SSL * s,const struct hm_header_st * msg_hdr)596 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr)
597 {
598 hm_fragment *frag = NULL;
599 pitem *item = NULL;
600 int i = -1, is_complete;
601 unsigned char seq64be[8];
602 size_t frag_len = msg_hdr->frag_len;
603 size_t readbytes;
604
605 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
606 msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
607 goto err;
608
609 if (frag_len == 0) {
610 return DTLS1_HM_FRAGMENT_RETRY;
611 }
612
613 /* Try to find item in queue */
614 memset(seq64be, 0, sizeof(seq64be));
615 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
616 seq64be[7] = (unsigned char)msg_hdr->seq;
617 item = pqueue_find(s->d1->buffered_messages, seq64be);
618
619 if (item == NULL) {
620 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
621 if (frag == NULL)
622 goto err;
623 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
624 frag->msg_header.frag_len = frag->msg_header.msg_len;
625 frag->msg_header.frag_off = 0;
626 } else {
627 frag = (hm_fragment *)item->data;
628 if (frag->msg_header.msg_len != msg_hdr->msg_len) {
629 item = NULL;
630 frag = NULL;
631 goto err;
632 }
633 }
634
635 /*
636 * If message is already reassembled, this must be a retransmit and can
637 * be dropped. In this case item != NULL and so frag does not need to be
638 * freed.
639 */
640 if (frag->reassembly == NULL) {
641 unsigned char devnull[256];
642
643 while (frag_len) {
644 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
645 devnull,
646 frag_len >
647 sizeof(devnull) ? sizeof(devnull) :
648 frag_len, 0, &readbytes);
649 if (i <= 0)
650 goto err;
651 frag_len -= readbytes;
652 }
653 return DTLS1_HM_FRAGMENT_RETRY;
654 }
655
656 /* read the body of the fragment (header has already been read */
657 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
658 frag->fragment + msg_hdr->frag_off,
659 frag_len, 0, &readbytes);
660 if (i <= 0 || readbytes != frag_len)
661 i = -1;
662 if (i <= 0)
663 goto err;
664
665 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
666 (long)(msg_hdr->frag_off + frag_len));
667
668 if (!ossl_assert(msg_hdr->msg_len > 0))
669 goto err;
670 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
671 is_complete);
672
673 if (is_complete) {
674 OPENSSL_free(frag->reassembly);
675 frag->reassembly = NULL;
676 }
677
678 if (item == NULL) {
679 item = pitem_new(seq64be, frag);
680 if (item == NULL) {
681 i = -1;
682 goto err;
683 }
684
685 item = pqueue_insert(s->d1->buffered_messages, item);
686 /*
687 * pqueue_insert fails iff a duplicate item is inserted. However,
688 * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
689 * would have returned it and control would never have reached this
690 * branch.
691 */
692 if (!ossl_assert(item != NULL))
693 goto err;
694 }
695
696 return DTLS1_HM_FRAGMENT_RETRY;
697
698 err:
699 if (item == NULL)
700 dtls1_hm_fragment_free(frag);
701 return -1;
702 }
703
704 static int
dtls1_process_out_of_seq_message(SSL * s,const struct hm_header_st * msg_hdr)705 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st *msg_hdr)
706 {
707 int i = -1;
708 hm_fragment *frag = NULL;
709 pitem *item = NULL;
710 unsigned char seq64be[8];
711 size_t frag_len = msg_hdr->frag_len;
712 size_t readbytes;
713
714 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len)
715 goto err;
716
717 /* Try to find item in queue, to prevent duplicate entries */
718 memset(seq64be, 0, sizeof(seq64be));
719 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
720 seq64be[7] = (unsigned char)msg_hdr->seq;
721 item = pqueue_find(s->d1->buffered_messages, seq64be);
722
723 /*
724 * If we already have an entry and this one is a fragment, don't discard
725 * it and rather try to reassemble it.
726 */
727 if (item != NULL && frag_len != msg_hdr->msg_len)
728 item = NULL;
729
730 /*
731 * Discard the message if sequence number was already there, is too far
732 * in the future, already in the queue or if we received a FINISHED
733 * before the SERVER_HELLO, which then must be a stale retransmit.
734 */
735 if (msg_hdr->seq <= s->d1->handshake_read_seq ||
736 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
737 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED)) {
738 unsigned char devnull[256];
739
740 while (frag_len) {
741 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
742 devnull,
743 frag_len >
744 sizeof(devnull) ? sizeof(devnull) :
745 frag_len, 0, &readbytes);
746 if (i <= 0)
747 goto err;
748 frag_len -= readbytes;
749 }
750 } else {
751 if (frag_len != msg_hdr->msg_len) {
752 return dtls1_reassemble_fragment(s, msg_hdr);
753 }
754
755 if (frag_len > dtls1_max_handshake_message_len(s))
756 goto err;
757
758 frag = dtls1_hm_fragment_new(frag_len, 0);
759 if (frag == NULL)
760 goto err;
761
762 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
763
764 if (frag_len) {
765 /*
766 * read the body of the fragment (header has already been read
767 */
768 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
769 frag->fragment, frag_len, 0,
770 &readbytes);
771 if (i<=0 || readbytes != frag_len)
772 i = -1;
773 if (i <= 0)
774 goto err;
775 }
776
777 item = pitem_new(seq64be, frag);
778 if (item == NULL)
779 goto err;
780
781 item = pqueue_insert(s->d1->buffered_messages, item);
782 /*
783 * pqueue_insert fails iff a duplicate item is inserted. However,
784 * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
785 * would have returned it. Then, either |frag_len| !=
786 * |msg_hdr->msg_len| in which case |item| is set to NULL and it will
787 * have been processed with |dtls1_reassemble_fragment|, above, or
788 * the record will have been discarded.
789 */
790 if (!ossl_assert(item != NULL))
791 goto err;
792 }
793
794 return DTLS1_HM_FRAGMENT_RETRY;
795
796 err:
797 if (item == NULL)
798 dtls1_hm_fragment_free(frag);
799 return 0;
800 }
801
dtls_get_reassembled_message(SSL * s,int * errtype,size_t * len)802 static int dtls_get_reassembled_message(SSL *s, int *errtype, size_t *len)
803 {
804 unsigned char wire[DTLS1_HM_HEADER_LENGTH];
805 size_t mlen, frag_off, frag_len;
806 int i, ret, recvd_type;
807 struct hm_header_st msg_hdr;
808 size_t readbytes;
809 int chretran = 0;
810
811 *errtype = 0;
812
813 redo:
814 /* see if we have the required fragment already */
815 ret = dtls1_retrieve_buffered_fragment(s, &frag_len);
816 if (ret < 0) {
817 /* SSLfatal() already called */
818 return 0;
819 }
820 if (ret > 0) {
821 s->init_num = frag_len;
822 *len = frag_len;
823 return 1;
824 }
825
826 /* read handshake message header */
827 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &recvd_type, wire,
828 DTLS1_HM_HEADER_LENGTH, 0, &readbytes);
829 if (i <= 0) { /* nbio, or an error */
830 s->rwstate = SSL_READING;
831 *len = 0;
832 return 0;
833 }
834 if (recvd_type == SSL3_RT_CHANGE_CIPHER_SPEC) {
835 if (wire[0] != SSL3_MT_CCS) {
836 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
837 SSL_R_BAD_CHANGE_CIPHER_SPEC);
838 goto f_err;
839 }
840
841 memcpy(s->init_buf->data, wire, readbytes);
842 s->init_num = readbytes - 1;
843 s->init_msg = s->init_buf->data + 1;
844 s->s3.tmp.message_type = SSL3_MT_CHANGE_CIPHER_SPEC;
845 s->s3.tmp.message_size = readbytes - 1;
846 *len = readbytes - 1;
847 return 1;
848 }
849
850 /* Handshake fails if message header is incomplete */
851 if (readbytes != DTLS1_HM_HEADER_LENGTH) {
852 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
853 goto f_err;
854 }
855
856 /* parse the message fragment header */
857 dtls1_get_message_header(wire, &msg_hdr);
858
859 mlen = msg_hdr.msg_len;
860 frag_off = msg_hdr.frag_off;
861 frag_len = msg_hdr.frag_len;
862
863 /*
864 * We must have at least frag_len bytes left in the record to be read.
865 * Fragments must not span records.
866 */
867 if (frag_len > RECORD_LAYER_get_rrec_length(&s->rlayer)) {
868 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_LENGTH);
869 goto f_err;
870 }
871
872 /*
873 * if this is a future (or stale) message it gets buffered
874 * (or dropped)--no further processing at this time
875 * While listening, we accept seq 1 (ClientHello with cookie)
876 * although we're still expecting seq 0 (ClientHello)
877 */
878 if (msg_hdr.seq != s->d1->handshake_read_seq) {
879 if (!s->server
880 || msg_hdr.seq != 0
881 || s->d1->handshake_read_seq != 1
882 || wire[0] != SSL3_MT_CLIENT_HELLO
883 || s->statem.hand_state != DTLS_ST_SW_HELLO_VERIFY_REQUEST) {
884 *errtype = dtls1_process_out_of_seq_message(s, &msg_hdr);
885 return 0;
886 }
887 /*
888 * We received a ClientHello and sent back a HelloVerifyRequest. We
889 * now seem to have received a retransmitted initial ClientHello. That
890 * is allowed (possibly our HelloVerifyRequest got lost).
891 */
892 chretran = 1;
893 }
894
895 if (frag_len && frag_len < mlen) {
896 *errtype = dtls1_reassemble_fragment(s, &msg_hdr);
897 return 0;
898 }
899
900 if (!s->server
901 && s->d1->r_msg_hdr.frag_off == 0
902 && s->statem.hand_state != TLS_ST_OK
903 && wire[0] == SSL3_MT_HELLO_REQUEST) {
904 /*
905 * The server may always send 'Hello Request' messages -- we are
906 * doing a handshake anyway now, so ignore them if their format is
907 * correct. Does not count for 'Finished' MAC.
908 */
909 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) {
910 if (s->msg_callback)
911 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
912 wire, DTLS1_HM_HEADER_LENGTH, s,
913 s->msg_callback_arg);
914
915 s->init_num = 0;
916 goto redo;
917 } else { /* Incorrectly formatted Hello request */
918
919 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
920 goto f_err;
921 }
922 }
923
924 if (!dtls1_preprocess_fragment(s, &msg_hdr)) {
925 /* SSLfatal() already called */
926 goto f_err;
927 }
928
929 if (frag_len > 0) {
930 unsigned char *p =
931 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
932
933 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
934 &p[frag_off], frag_len, 0, &readbytes);
935
936 /*
937 * This shouldn't ever fail due to NBIO because we already checked
938 * that we have enough data in the record
939 */
940 if (i <= 0) {
941 s->rwstate = SSL_READING;
942 *len = 0;
943 return 0;
944 }
945 } else {
946 readbytes = 0;
947 }
948
949 /*
950 * XDTLS: an incorrectly formatted fragment should cause the handshake
951 * to fail
952 */
953 if (readbytes != frag_len) {
954 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_LENGTH);
955 goto f_err;
956 }
957
958 if (chretran) {
959 /*
960 * We got a new ClientHello with a message sequence of 0.
961 * Reset the read/write sequences back to the beginning.
962 * We process it like this is the first time we've seen a ClientHello
963 * from the client.
964 */
965 s->d1->handshake_read_seq = 0;
966 s->d1->next_handshake_write_seq = 0;
967 }
968
969 /*
970 * Note that s->init_num is *not* used as current offset in
971 * s->init_buf->data, but as a counter summing up fragments' lengths: as
972 * soon as they sum up to handshake packet length, we assume we have got
973 * all the fragments.
974 */
975 *len = s->init_num = frag_len;
976 return 1;
977
978 f_err:
979 s->init_num = 0;
980 *len = 0;
981 return 0;
982 }
983
984 /*-
985 * for these 2 messages, we need to
986 * ssl->enc_read_ctx re-init
987 * ssl->rlayer.read_sequence zero
988 * ssl->s3.read_mac_secret re-init
989 * ssl->session->read_sym_enc assign
990 * ssl->session->read_compression assign
991 * ssl->session->read_hash assign
992 */
dtls_construct_change_cipher_spec(SSL * s,WPACKET * pkt)993 int dtls_construct_change_cipher_spec(SSL *s, WPACKET *pkt)
994 {
995 if (s->version == DTLS1_BAD_VER) {
996 s->d1->next_handshake_write_seq++;
997
998 if (!WPACKET_put_bytes_u16(pkt, s->d1->handshake_write_seq)) {
999 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1000 return 0;
1001 }
1002 }
1003
1004 return 1;
1005 }
1006
1007 #ifndef OPENSSL_NO_SCTP
1008 /*
1009 * Wait for a dry event. Should only be called at a point in the handshake
1010 * where we are not expecting any data from the peer except an alert.
1011 */
dtls_wait_for_dry(SSL * s)1012 WORK_STATE dtls_wait_for_dry(SSL *s)
1013 {
1014 int ret, errtype;
1015 size_t len;
1016
1017 /* read app data until dry event */
1018 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1019 if (ret < 0) {
1020 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1021 return WORK_ERROR;
1022 }
1023
1024 if (ret == 0) {
1025 /*
1026 * We're not expecting any more messages from the peer at this point -
1027 * but we could get an alert. If an alert is waiting then we will never
1028 * return successfully. Therefore we attempt to read a message. This
1029 * should never succeed but will process any waiting alerts.
1030 */
1031 if (dtls_get_reassembled_message(s, &errtype, &len)) {
1032 /* The call succeeded! This should never happen */
1033 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
1034 return WORK_ERROR;
1035 }
1036
1037 s->s3.in_read_app_data = 2;
1038 s->rwstate = SSL_READING;
1039 BIO_clear_retry_flags(SSL_get_rbio(s));
1040 BIO_set_retry_read(SSL_get_rbio(s));
1041 return WORK_MORE_A;
1042 }
1043 return WORK_FINISHED_CONTINUE;
1044 }
1045 #endif
1046
dtls1_read_failed(SSL * s,int code)1047 int dtls1_read_failed(SSL *s, int code)
1048 {
1049 if (code > 0) {
1050 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1051 return 0;
1052 }
1053
1054 if (!dtls1_is_timer_expired(s) || ossl_statem_in_error(s)) {
1055 /*
1056 * not a timeout, none of our business, let higher layers handle
1057 * this. in fact it's probably an error
1058 */
1059 return code;
1060 }
1061 /* done, no need to send a retransmit */
1062 if (!SSL_in_init(s))
1063 {
1064 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1065 return code;
1066 }
1067
1068 return dtls1_handle_timeout(s);
1069 }
1070
dtls1_get_queue_priority(unsigned short seq,int is_ccs)1071 int dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1072 {
1073 /*
1074 * The index of the retransmission queue actually is the message sequence
1075 * number, since the queue only contains messages of a single handshake.
1076 * However, the ChangeCipherSpec has no message sequence number and so
1077 * using only the sequence will result in the CCS and Finished having the
1078 * same index. To prevent this, the sequence number is multiplied by 2.
1079 * In case of a CCS 1 is subtracted. This does not only differ CSS and
1080 * Finished, it also maintains the order of the index (important for
1081 * priority queues) and fits in the unsigned short variable.
1082 */
1083 return seq * 2 - is_ccs;
1084 }
1085
dtls1_retransmit_buffered_messages(SSL * s)1086 int dtls1_retransmit_buffered_messages(SSL *s)
1087 {
1088 pqueue *sent = s->d1->sent_messages;
1089 piterator iter;
1090 pitem *item;
1091 hm_fragment *frag;
1092 int found = 0;
1093
1094 iter = pqueue_iterator(sent);
1095
1096 for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) {
1097 frag = (hm_fragment *)item->data;
1098 if (dtls1_retransmit_message(s, (unsigned short)
1099 dtls1_get_queue_priority
1100 (frag->msg_header.seq,
1101 frag->msg_header.is_ccs), &found) <= 0)
1102 return -1;
1103 }
1104
1105 return 1;
1106 }
1107
dtls1_buffer_message(SSL * s,int is_ccs)1108 int dtls1_buffer_message(SSL *s, int is_ccs)
1109 {
1110 pitem *item;
1111 hm_fragment *frag;
1112 unsigned char seq64be[8];
1113
1114 /*
1115 * this function is called immediately after a message has been
1116 * serialized
1117 */
1118 if (!ossl_assert(s->init_off == 0))
1119 return 0;
1120
1121 frag = dtls1_hm_fragment_new(s->init_num, 0);
1122 if (frag == NULL)
1123 return 0;
1124
1125 memcpy(frag->fragment, s->init_buf->data, s->init_num);
1126
1127 if (is_ccs) {
1128 /* For DTLS1_BAD_VER the header length is non-standard */
1129 if (!ossl_assert(s->d1->w_msg_hdr.msg_len +
1130 ((s->version ==
1131 DTLS1_BAD_VER) ? 3 : DTLS1_CCS_HEADER_LENGTH)
1132 == (unsigned int)s->init_num)) {
1133 dtls1_hm_fragment_free(frag);
1134 return 0;
1135 }
1136 } else {
1137 if (!ossl_assert(s->d1->w_msg_hdr.msg_len +
1138 DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num)) {
1139 dtls1_hm_fragment_free(frag);
1140 return 0;
1141 }
1142 }
1143
1144 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1145 frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1146 frag->msg_header.type = s->d1->w_msg_hdr.type;
1147 frag->msg_header.frag_off = 0;
1148 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1149 frag->msg_header.is_ccs = is_ccs;
1150
1151 /* save current state */
1152 frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1153 frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1154 frag->msg_header.saved_retransmit_state.compress = s->compress;
1155 frag->msg_header.saved_retransmit_state.session = s->session;
1156 frag->msg_header.saved_retransmit_state.epoch =
1157 DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer);
1158
1159 memset(seq64be, 0, sizeof(seq64be));
1160 seq64be[6] =
1161 (unsigned
1162 char)(dtls1_get_queue_priority(frag->msg_header.seq,
1163 frag->msg_header.is_ccs) >> 8);
1164 seq64be[7] =
1165 (unsigned
1166 char)(dtls1_get_queue_priority(frag->msg_header.seq,
1167 frag->msg_header.is_ccs));
1168
1169 item = pitem_new(seq64be, frag);
1170 if (item == NULL) {
1171 dtls1_hm_fragment_free(frag);
1172 return 0;
1173 }
1174
1175 pqueue_insert(s->d1->sent_messages, item);
1176 return 1;
1177 }
1178
dtls1_retransmit_message(SSL * s,unsigned short seq,int * found)1179 int dtls1_retransmit_message(SSL *s, unsigned short seq, int *found)
1180 {
1181 int ret;
1182 /* XDTLS: for now assuming that read/writes are blocking */
1183 pitem *item;
1184 hm_fragment *frag;
1185 unsigned long header_length;
1186 unsigned char seq64be[8];
1187 struct dtls1_retransmit_state saved_state;
1188
1189 /* XDTLS: the requested message ought to be found, otherwise error */
1190 memset(seq64be, 0, sizeof(seq64be));
1191 seq64be[6] = (unsigned char)(seq >> 8);
1192 seq64be[7] = (unsigned char)seq;
1193
1194 item = pqueue_find(s->d1->sent_messages, seq64be);
1195 if (item == NULL) {
1196 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1197 *found = 0;
1198 return 0;
1199 }
1200
1201 *found = 1;
1202 frag = (hm_fragment *)item->data;
1203
1204 if (frag->msg_header.is_ccs)
1205 header_length = DTLS1_CCS_HEADER_LENGTH;
1206 else
1207 header_length = DTLS1_HM_HEADER_LENGTH;
1208
1209 memcpy(s->init_buf->data, frag->fragment,
1210 frag->msg_header.msg_len + header_length);
1211 s->init_num = frag->msg_header.msg_len + header_length;
1212
1213 dtls1_set_message_header_int(s, frag->msg_header.type,
1214 frag->msg_header.msg_len,
1215 frag->msg_header.seq, 0,
1216 frag->msg_header.frag_len);
1217
1218 /* save current state */
1219 saved_state.enc_write_ctx = s->enc_write_ctx;
1220 saved_state.write_hash = s->write_hash;
1221 saved_state.compress = s->compress;
1222 saved_state.session = s->session;
1223 saved_state.epoch = DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer);
1224
1225 s->d1->retransmitting = 1;
1226
1227 /* restore state in which the message was originally sent */
1228 s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1229 s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1230 s->compress = frag->msg_header.saved_retransmit_state.compress;
1231 s->session = frag->msg_header.saved_retransmit_state.session;
1232 DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer,
1233 frag->msg_header.
1234 saved_retransmit_state.epoch);
1235
1236 ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1237 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1238
1239 /* restore current state */
1240 s->enc_write_ctx = saved_state.enc_write_ctx;
1241 s->write_hash = saved_state.write_hash;
1242 s->compress = saved_state.compress;
1243 s->session = saved_state.session;
1244 DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer, saved_state.epoch);
1245
1246 s->d1->retransmitting = 0;
1247
1248 (void)BIO_flush(s->wbio);
1249 return ret;
1250 }
1251
dtls1_set_message_header(SSL * s,unsigned char mt,size_t len,size_t frag_off,size_t frag_len)1252 void dtls1_set_message_header(SSL *s,
1253 unsigned char mt, size_t len,
1254 size_t frag_off, size_t frag_len)
1255 {
1256 if (frag_off == 0) {
1257 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1258 s->d1->next_handshake_write_seq++;
1259 }
1260
1261 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1262 frag_off, frag_len);
1263 }
1264
1265 /* don't actually do the writing, wait till the MTU has been retrieved */
1266 static void
dtls1_set_message_header_int(SSL * s,unsigned char mt,size_t len,unsigned short seq_num,size_t frag_off,size_t frag_len)1267 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1268 size_t len, unsigned short seq_num,
1269 size_t frag_off, size_t frag_len)
1270 {
1271 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1272
1273 msg_hdr->type = mt;
1274 msg_hdr->msg_len = len;
1275 msg_hdr->seq = seq_num;
1276 msg_hdr->frag_off = frag_off;
1277 msg_hdr->frag_len = frag_len;
1278 }
1279
1280 static void
dtls1_fix_message_header(SSL * s,size_t frag_off,size_t frag_len)1281 dtls1_fix_message_header(SSL *s, size_t frag_off, size_t frag_len)
1282 {
1283 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1284
1285 msg_hdr->frag_off = frag_off;
1286 msg_hdr->frag_len = frag_len;
1287 }
1288
dtls1_write_message_header(SSL * s,unsigned char * p)1289 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p)
1290 {
1291 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1292
1293 *p++ = msg_hdr->type;
1294 l2n3(msg_hdr->msg_len, p);
1295
1296 s2n(msg_hdr->seq, p);
1297 l2n3(msg_hdr->frag_off, p);
1298 l2n3(msg_hdr->frag_len, p);
1299
1300 return p;
1301 }
1302
dtls1_get_message_header(unsigned char * data,struct hm_header_st * msg_hdr)1303 void dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1304 {
1305 memset(msg_hdr, 0, sizeof(*msg_hdr));
1306 msg_hdr->type = *(data++);
1307 n2l3(data, msg_hdr->msg_len);
1308
1309 n2s(data, msg_hdr->seq);
1310 n2l3(data, msg_hdr->frag_off);
1311 n2l3(data, msg_hdr->frag_len);
1312 }
1313
dtls1_set_handshake_header(SSL * s,WPACKET * pkt,int htype)1314 int dtls1_set_handshake_header(SSL *s, WPACKET *pkt, int htype)
1315 {
1316 unsigned char *header;
1317
1318 if (htype == SSL3_MT_CHANGE_CIPHER_SPEC) {
1319 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1320 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
1321 s->d1->handshake_write_seq, 0, 0);
1322 if (!WPACKET_put_bytes_u8(pkt, SSL3_MT_CCS))
1323 return 0;
1324 } else {
1325 dtls1_set_message_header(s, htype, 0, 0, 0);
1326 /*
1327 * We allocate space at the start for the message header. This gets
1328 * filled in later
1329 */
1330 if (!WPACKET_allocate_bytes(pkt, DTLS1_HM_HEADER_LENGTH, &header)
1331 || !WPACKET_start_sub_packet(pkt))
1332 return 0;
1333 }
1334
1335 return 1;
1336 }
1337
dtls1_close_construct_packet(SSL * s,WPACKET * pkt,int htype)1338 int dtls1_close_construct_packet(SSL *s, WPACKET *pkt, int htype)
1339 {
1340 size_t msglen;
1341
1342 if ((htype != SSL3_MT_CHANGE_CIPHER_SPEC && !WPACKET_close(pkt))
1343 || !WPACKET_get_length(pkt, &msglen)
1344 || msglen > INT_MAX)
1345 return 0;
1346
1347 if (htype != SSL3_MT_CHANGE_CIPHER_SPEC) {
1348 s->d1->w_msg_hdr.msg_len = msglen - DTLS1_HM_HEADER_LENGTH;
1349 s->d1->w_msg_hdr.frag_len = msglen - DTLS1_HM_HEADER_LENGTH;
1350 }
1351 s->init_num = (int)msglen;
1352 s->init_off = 0;
1353
1354 if (htype != DTLS1_MT_HELLO_VERIFY_REQUEST) {
1355 /* Buffer the message to handle re-xmits */
1356 if (!dtls1_buffer_message(s, htype == SSL3_MT_CHANGE_CIPHER_SPEC
1357 ? 1 : 0))
1358 return 0;
1359 }
1360
1361 return 1;
1362 }
1363